The CSS from an epub file must be converted (by kindlegen) to HTML 3.2 attributes in the mobi file, so keeping the CSS extremely simple is always the best approach. Unfortunately, the only way to find out what works best (or at all) is through trial and error (and of course by looking through the threads here at MR to find what others may have stumbled upon).

I'm not familiar with the possibilities of styling for the Kindle device (mobi).

I assumed that Amazon would provide a default styling sheet for epub so that the mobi result would look good but was unable to find one (searching with Google and on the Amazon site).

Can someone suggest a good default CSS which I could use in in my epub so that I get a good mobi result?

What CSS in an ePub will convert well to MOBI depends a lot on what conversion tool is used.

You might give the Amazon Kindle Publishing Guidelines ( http://www.amazon.com/gp/feature.htm...cId=1000234621 ) a read with particular attention to the "HTML Guidelines" section. Any tag attribute supported in MOBI should be supported by most conversion tools when encountered in its CSS equivalent.